3 ways to good health, by living in sync with your body clock : NPR

A return to “standard time” is good for our health, according to sleep scientists, but the time change can have devastating effects and our bodies must also adjust to more hours of darkness as winter approaches.

The body is a perfect machine that determines time. And growing evidence shows that if you align your daily habits with… your circadian rhythms – including when you sleep, eat and exercise – you can help prevent chronic disease and improve good health.

Let's start with a quick introduction: “Your body is filled with clocks,” explains Emily Manukyanresearcher and chronobiologist at the Salk Institute for Biological Studies. In addition to the master clock in your brain, there are mechanisms in every organ and in your cells that tell time.

“Every cell in your body that has DNA has a molecular clock that keeps time,” she says. They are all part of your body's circadian system, helping you stay in sync with the 24-hour cycle.

But our bodies don't maintain perfect time on their own. Every day we deviate a little from the 24-hour cycle and need to reset, explains the Salk Institute researcher. Satchin Pandaauthor Circadian Code: Lose weight, energize, and transform your health from morning to midnight.

“The master clock in your brain coordinates all the other clocks through a number of different signals,” explains Manukian, including external signals such as light, food and movement. And this is why the timing of our habits can play a crucial role in synchronizing our clocks.

Sunlight serves as an external signal to resynchronize the master clock. Therefore, it is useful to open the blinds in the morning and spend time in the fresh air.

And it turns out that our first bite of food each day also serves as an external signal to synchronize the clocks in our digestive system and throughout the body.

“Food is also a signal to reset the clock, especially the gut,” says Manukyan. “That’s one reason why it’s important to make sure you eat at the right times and in light.”

Eating food is a signal to wake up the digestive and metabolic organs, which are tuned to function best throughout the day. By nightfall, the metabolic system is also ready to rest.

“When you sleep, your body expects to be hungry. And so it shuts down the part of the system that takes glucose from the blood and stores it,” she explains.

When people eat before bed or in the middle of the night, their metabolic organs are not optimized to do their job. The mismatch can lead to poor blood sugar control. Her research shows that limiting the number of hours you eat during the day to around a 10-hour window can lead to significant improvements in metabolic health.

There is ample evidence that eating out of sync with your circadian rhythm can increase your risk of metabolic diseases, including diabetes and obesity. Research shows that shift workers who work shifts at night shifts have a higher risk the development of these conditions is partly due to disruption of natural rhythms.

And when it comes to exercise, some people find they work out best in the morning, others in the afternoon, says Dr. PhylissDirector of the Center for Sleep and Circadian Medicine at Northwestern University Feinberg School of Medicine. But science shows that exercising late at night, just before bed, can disrupt your sleep.

“There is a peak time for almost every physiological process,” Zee says. “Feeding times, exercise times, physical activity all help synchronize your body's clock,” she says.

If you eat dinner and go to bed at almost the same time, your “habit” can pay off. “Science shows that regularity is very important for the circadian system and health,” says Zee.

And while each person is unique, she says, a general rule of thumb is to begin limiting your exposure to light, food and strenuous exercise, starting a few hours before bed.

But as scientists learned more about the importance of synchronizing our body clocks, society moved in the opposite direction. Manoukian cites advertisements for midnight menus and 24-hour work and entertainment as examples of our 24/7 modern lives.

One way to combat this is to track your daily habits. Michelle Pittsley, who lives in Vista, California, started using an app called my Circadian Clock record her food and blood sugar levels. She says it helped her stick to her time-restricted eating routine and track her progress. The app was developed by Salk scientists as a research tool and is used in Salk Institute research. It's free for any adult who downloads it. The app gives recommendations on when to sleep, eat and exercise. (Note: If you sign up, you will share data with researchers.)

When our circadian rhythms are disrupted, we increase our risk of developing chronic diseases, including obesity, diabetes, heart disease, fatty liver disease, bowel disease and common cancers, Panda and Manukian say. If you want to be more intentional about aligning your habits to improve your health, here are three strategies worth trying.

1. Avoid late-night snacks and limit your meal times.

People who limit their food intake to a ten-hour window may reduce their risk of developing type 2 diabetes, Manukian said. She and Panda co-authored a study that included 108 adults, average age 59, who had symptoms of metabolic disease. They found that those who adhered to time-restricted eating saw significant improvement. decreased hemoglobin A1c levels (this is a person's average glucose level over several months) compared to participants who did not restrict their eating window.

Participants were not asked to cut calories, but only limited their eating window for a period of three months.

“It was interesting to see that just time-restricted eating could reduce the risk of developing type 2 diabetes by 60%,” says Manukian, since lowering blood sugar levels, if maintained, reduces the risk of the disease.

Research also suggests that eating your main meal in the afternoon rather than the evening may be beneficial for those looking to lose weight. A study conducted in Spain showed those who ate early lost 25 percent more weight than those who eat late. Panda says that when his mother gave up her nightly snack, which included tea with sugar and milk, and the occasional snack, one change led to a significant drop in her blood sugar levels.

2. Go to bed at almost the same time.

“Keeping the same sleep schedule is optimal,” says Manukyan. Consistency gives your body the ability to anticipate and synchronize your internal clock. During sleep, garbage is cleared from our brainAnd memories are consolidatedand there is plenty of evidence that rest is critical to our health.

But don't beat yourself up when you're out late at night. And of course there will be disruptions due to travel, work deadlines or weekend celebrations. “Having your circadian system go haywire is not the same as breaking your arm,” says Manukyan. Think about the harm of a chaotic schedule, just as dripping water can destroy a stone. “Small impacts from time to time can wear out the system,” she says. As a result, you may feel slower and older.

Eat many rituals before bed Promote a good night's sleep, including limiting light before bed and sleeping in the dark. Zee's research shows even a small amount of light during sleep may have adverse effects on the cardiovascular system and metabolism.

3. Do exercises at a time convenient for you, but not too late in the evening.

According to Zee, whether you're a morning lark or a night owl can affect the ideal time to exercise, so it will vary from person to person. “The best time to exercise depends in part on what we call your chronotype,” she says, which is a person's innate preference for when to sleep, or when they feel more alert and energetic. One way to assess your propensity is to Morning-Evening questionnaire.

“If you're a morning person, morning exercise can be helpful,” Zee says, creating a consistent structure, but people who become more alert throughout the day may want to save it for later. As people juggle competing responsibilities, exercise can be squeezed into a time that fits your calendar, even if it's not your body clock's preferred time. She says it's important to remember that exercise is beneficial no matter what time you do it.

But keep this in mind: “Exercise is a stimulant signal telling your body it's time to stay awake,” says Manukian, so it's no surprise that recent study shows that exercise immediately before bed can disrupt sleep quality .